Scuba Diving Terms and Phrases: A

Advanced Open Water: Follow up certification after Open-Water Diver; allows for deeper

Air: A gas mixture containing 21percent oxygen, 78 percent nitrogen, and 1 percent other gasses (mainly argon); compressed air is held in a tank for scuba diving.

Apnea: Breath-holding; apnea diving is a type of freediving, but in scuba diving you should never hold your breath.

Ascent: Rising to the surface when diving; typically at the end of a dive.

Ascent Rate: How quickly a diver returns to the surface. You should never ascend faster than your bubbles as a safety precaution.

Scuba Diving Terms and Phrases: B

Backroll: Entering the water from the side of the boat, back first.

BC/BCD: Buoyancy Compensator. This is the harness divers wear that hold the air tank and connects to the regulator.

Bends/Bent: The pain a diver feels when suffering from Decompression Sickness (DCS). See DCS definition below. The bends often occur from ascending too quickly.

Boat Dive: Scuba diving that requires a boat ride to the dive site.

Bootie: Scuba gear divers wear with open-heel fins. Booties can range from thin (1 mm or less) to thick (7 mm) neoprene and protect your feet from the cold as well as sharp rocks and other hazardous things you could step on when shore diving.

Bottom Time: The length of your dive.

Buddy: The person you dive with; this is the person you discuss a dive plan with and you are both responsible for keeping each other safe.

Buoyancy: (Positive, Negative, Neutral) Buoyancy refers to your position in the water. Things that sink are negatively buoyant; things that float are positively buoyant; scuba divers should be neutrally buoyant (floating in the middle).

Scuba Diving Terms and Phrases: C

C-Card: Proof of scuba certification that you receive after completing your training course. This is necessary to go diving without an instructor for open water divers and is proof of any secondary/specialty scuba training and certifications you have.

Call: To "call a dive" means that you are choosing or being told to end the dive and return to the surface.

Cave: A hollow place in the ground, typically of natural formation.

Cave Diving: Entering a water-filled cave system either on scuba or freediving. Cave diving can extend thousands of feet into a cave system for people who are properly trained.

Cavern: A semi-enclosed area (often a rock formation) where you can still see the entrance and

Certified Diver: Someone who has completed scuba diving lessons through a training organization and is able to dive without an instructor.

Certification Agency: An organization like PADI, NAUI or SSI that trains people to scuba dive. There are over 100 agencies that do this, but not all certifications are valid worldwide.

Check-Out Dive: These are the dives completed outside of a pool (can be in a lake, ocean, spring, quarry, etc.) to prove that you’ve mastered a set of scuba skills and are necessary to complete scuba certification.

Confined Water Dive: Dives conducted in a pool or other shallow, current-free underwater environment so that students can master training and skills in a safe, controlled environment before completing open-water check-out dives.

Scuba Diving Terms and Phrases: D

DAN: Divers Alert Network

DCS/Decompression Sickness: When bubbles of gas (often nitrogen) get trapped inside of the body. There are varying levels of severity, and can be caused by swimming to the surface too quickly.

Depth Gauge: A piece of scuba equipment that monitors how deep you are during your dive. Most dive computers serve as a replacement for depth gauges.

Dedicated Dive Resort: Accommodations that focus on scuba diving experiences. They often have a dive shop onsite, and include diving in the booking fees.

Dive Computer: A piece of scuba gear that monitors depth, bottom time and a ton of other information about each dive you complete. All dive computers are different, but they are an alternative to planning dives with dive tables.

Dive Instructor: This person has gone through many trainings and certifications (open-water, advanced-open water, rescue diver, divemaster and more) so that they can teach others how to scuba dive.

Dive Light: A flashlight designed for use underwater.

Dive Operator: A store, boat or lcoation that will take you to go diving and often can certify you as well.

Dive Table: Tool that helps determine how long you can safely stay underwater at different depths. Developed by the military to keep divers safe from decompression sickness

Divemaster: A professional-level scuba diver who has logged at least 60 dives and who is trained to assist instructors on dive boats and during certification courses.

DPV: Diver Propulsion Vehicle. A handheld and operated scooter or motor device that allows divers to move faster underwater.

Drift Dive: Diving in a current, often from a boat. Once the dive is complete, the boat picks you up at the surface.

Dry Bag: A bag to keep any items dry that aren’t waterproof.

Drysuit: A type of exposure suit that keeps you dry while diving; used in cold-water dive conditions.

Scuba Diving Terms and Phrases: E

EAN: Enriched Air Nitrox. This is a form of mixed-gas scuba diving.

Entry: Getting into the water either from shore, boat, etc.

Equalize/Equalization: Putting air into an open area to compensate for the change in pressure. (Most commonly ear equalization for scuba divers.)

Exposure Suit: A garment worn to keep divers warm and help protect them from cuts, scrapes and other elements.

Scuba Diving Terms and Phrases: F

Fins: The scuba gear that you wear on your feet to help you swim faster/with less effort.

First Stage: Part of a scuba regulator; this attaches to the air tank.

Freediving: Diving deep or staying underwater for extended periods of time without an air tank.

Frog Kick: A technique for kicking your fins underwater. The bottoms of your feet move at each other like you’re sitting Indian style to propel you forward. This is a helpful technique to avoid kicking up sand.

FSW: Feet of Sea Water

Full-Foot Fin: A fin that covers your entire foot and most often doesn't require you to wear a bootie.

Scuba Diving Terms and Phrases: G, H, I, J, K, L

Giant Stride: A method of getting in the water where you take a large step off the boat or dock.

Hood: Scuba gear worn over your head to help keep you warm and protect from the elements.

Hyperbaric Chamber: Air-tight chamber that can simulate the ambient pressure at altitude or at depth. This is used for treating DCS.

Inflator Valve: A manually operated valve that puts compressed air into the buoyancy bladders of a BCD or into a dry suit.

Jonline/Anchor Line: A line designed to attach to an anchor other attachment at the bottom of the seafloor. This helps guide divers to the site and allows the diver to stay in the water column regardless of wave action during decompression stops.

Liveaboard: A cruise ship, yacht or other overnight boat that is tailored to scuba divers. Most often, this will have accommodations including beds, bathrooms, gear rentals, tanks and include meals.

Logbook: A record of the scuba dives you've completed. This includes how deep you dived, your bottom time, who you dived with, where you dived, what you saw, how long your surface interval was, and other information relevant to your dive.

Knot: The velocity unit of one nautical mile

Scuba Diving Terms and Phrases: M

Mask: The scuba gear you wear over your face and nose.

Mask Clearing: Removing water that has gotten into your mask. You learn this skill in your open-water certification course.

Scuba Diving Terms and Phrases: N

Nitrogen Narcosis (Rapture of the Deep): An altered mental state that occurs when nitrogen enters the bloodstream at pressure. Divers experience this differently, but commonly compare it to feeling slightly intoxicated.

Nitrox: For recreational diving, Nitrox (or Enriched Air Nitrox) refers to a mixture of nitrogen and oxygen where the oxygen concentration is more than 21 percent (which is the percentage of oxygen found in normal air). Most commonly refers to 32 percent oxygen in a tank.

No Fly/No Fly Time: The recommended timeframe you should wait between your last dive and getting on an airplane. The changes in altitude can cause DCS and other issues if flying happens too soon after scuba dives.

Scuba Diving Terms and Phrases: O

O-Ring: Often made of rubber, these doughnut-shaped rings are used in various pieces of scuba gear to prevent air or water from getting in or out of that piece of gear.

Octo/Octopus: This is a secondary regulator used for emergency situations such as buddy breathing or the failure of your main regulator.

Off Gas:

Open heel fin:

Open Water: Recreational diving (outside of a swimming pool) with no overhead environments and most often at depths no more than 90 feet. Open water certification is the first true scuba diving certification you can get.

Overhead Environment: Any situation (inside a shipwreck, cave, cavern, ice, etc.) where there is an object blocking a straight route upward to the surface.

Scuba Diving Terms and Phrases: P

Pressure Gauge: A device used to measure how much air you have left in your scuba tank.

Profile (Dive Profile): An overview of your dive. This is planned before the dive, and covers how deep you will go, how long you will be underwater, how far you plan to travel and other factors.

PSI: Pounds per square inch. Measure of gas pressure

Purge: To remove contents of something; most often removing any water from your regulator.

Scuba Diving Terms and Phrases: Q, R, S

Repetitive Dives: Multiple dives completed during the same day, without many hours in between.

Safety Stop: A 3-minute "hover" at the end of your dive made between 15-20 feet. This is a precaution to be sure that excess nitrogen has a chance to get out of your bloodstream so that DCS symptoms don't appear.

Shore Dive: A dive where you can walk from the shore into the water and find a dive site nearby.

Snorkel: A piece of gear used on the surface to breathe in place of your regulator.

Squeeze: Pain or discomfort (often in a mask, ears, and other enclosed areas, associated with the change in pressure from diving.

Surface Interval: Amount of time you're on the surface (or in the water above 10 feet if snorkeling).

Scuba Diving Terms and Phrases: T, U, V

Technical/Tech (Diving, Limits): Technical diving is any dive that's deeper than recreational limits. This includes cave diving, diving with special gas mixtures, dives exceeding 120 feet, and other dives that require special training.

Thermocline: A point underwater where the temperature drastically changes. Often this is visible as the two temperature "layers" meet.

Tide: The alternate rising and falling of the sea.

Vertigo: Dizziness caused by pressure differences in the inner ear. Can sometimes be a sign of trauma within the ear.

Viz/Visibility: Usually measured in feet or meters; how far away you can clearly see underwater.

Scuba Diving Terms and Phrases: W, X, Y, Z

Wall Dive: Dives that face a vertical wall, often a wall of coral reef.

Weight Belt: A piece of gear used when your BC is not weight-integrated. Weight belts hold the amount of weight a diver needs to keep from floating to the surface during dives.

Weight/Lead: Dive weights come in specified amounts and are added to a weight-integrated BC or a weight belt to keep you negatively buoyant.

Wetsuit: A tightly fitting neoprene suit that keeps you warm by allowing a small amount of water inside the suit. This comes in variations of thickness (from a a very thin "skin" to 1 mm, 3 mm, 5 mm, and 7 mm of thickness).

Wreck Diving: Diving shipwrecks, some of them unintentionally sunk and others are sunk to create artificial coral reefs. Specialty training is required to dive inside a wreck that has an overhead environment.